Machine for flotation of ores



Dec. 18, 1934.

A. W. FAHRENWALD MACHINE FOR FLOTATION GP 01235 2 Sheets-Sheet l FiledMay 2'7. 1927 lNvlTToR .AZWM/wuwda ATTORNEYS 1934- A. w. FAHRENWALD1,984,356

MACHINE FOR FLOTATION 0F ORES Filed May 27, 1927 2 Sheets-Sheet 2-lNVENTOR 2 1 ill/.Fbkremald 22/ 26 j 2 5 ATTORNEYSM iii Patented Dec.18, 1934 UNITED STATES PATENT OFFICE 14 Claims.

This invention relates to an improved machine for the flotation of oresand has for its object the provision of an apparatus of this characterthat will be more efficient and easier to handle. The invention residesin the combination and arrangement of parts as herein specified.

Referring to the drawings,

Figure 1 is a side elevation of -my'machine partly in section,

Figure 2 is a plan view of the machine,

Fig. 3 is a vertical sectional view ofthe invention,

Fig. 4 is a horizontal sectional view of the same,

Figure 5 is a perspective view of the impeller,

Figure dis a view partly in vertical section and partly in'elevation ofa modified impeller.

Referring now to Figures 1, 2, 3, and 4, nu-i metal 1 indicates a longrectangular tank, preferably of wood, and roughly as deep as it is wide.This tank is set within a suitable heavy framework 2, comprising timbersfor the tank to rest upon,'uprights supporting the walls of the tank andextending above same, these uprights being joined together at theirtopmost points by cross pieces suitable for the mounting of impellerdriving means. Below the first cross piece at a suitable distancetherefrom is a second cross piece 2' intended as a bearing support forthe impeller.

On theleft-hand side of the tank as shown in Figures 1 and 4 there is acompartment 3 which is intended for thereception of the ore to befloated. The tank itself is divided into two or more individual cells 4and 4* by means of weirs or vertical partitions 5.

Overflow edges or lips 6 are provided on front and rear edges of thetank for the froth concentrate and a lower one 11 for the extremetanking pulp on right hand side of the cell 4, the tank wall on thisside being somewhat lowered to provide such overflow edge. The weir 5and the lowered overflow edge are each preceded (measuring from left toright) by a baflie plate 9. On the right side of the weir 5 there is asecond baille 9 at some distance from 5. This baflle, together withthe'weir 5 and balfie 9, forms an overflow chamber 10 between the twocompartments of the cell.

In each cell compartment, there is located at approximately the centerthereof, means for agitating the liquid and ore to be contained in saidvcell and generating a froth therefrom. Such means comprise a casing 12terminating above the froth overflow level of the tank. This casing isheld in a perpendicular fixed positionin the hub 13 of the horizontaldisk 14 by means of a setscrew 13 or equivalent means.

The disk 14 is held above the bottom of the tank at a fixed distancetherefrom by means of lugs or spacers 15 cast integrally with the disk14 and being preferably notched to clear the impeller. These lugs 15have extensions or wings 16 above the disk also, the purpose of which isto provide baflies against which the contents of the cell are allowed tochurn, thus assisting the frothing action.

Communicating with each casing 12 andthe pulp overflow compartment 10 ofeach cell is a horizontal pipe passage way 17. -Within each casing 12there is a solid shaft 18, extending vertically down from the topframework of the cell, and supported insuitable bearings, the top bearing 19 being preferably of the combined thrust and radial ball typetaking both vertical and hori-. zontal loads. The lower bearing 19 is ofthe split box type.

An impeller 20 is bolted or otherwise attachedto the bottom of shaft 18,said impeller comprising a solid disk 21 having vanes 22 on its uppersurface as shown in detail in Figure 5.

Rotation may be imparted to the impeller and its shaft 18 by anysuitable means. I prefer to use, however, an individual electric motordrive for each impeller shaft. In this form of drive, there is anelectric motor 23 vertically mounted on the top framework of the cell insuch a manner that they may be connected by short belt drives to groovedpulleys 25 and fastened to the top of the shafts 19. I prefer to usemultiple grooved pulleys and V bolts.

For the removal of settled ore or other matter from the machine, thereis provided in the bottom of the tank in each cell an outlet and a plug26 The general operation of the machine 'is as follows:'-

Ore pulp is fed to the feed box-3 from whence it flows by ,gravitythrough'the horizontal pipe passage way'l'l into the casing 12 and ontothe rotating impeller 20, thence into the first cell of the machine. Asthe pulp continues to flow into the machine, cell No. 1 fills to theoverflow level of the weir 5 and any additional pulp flows into theoverflow compartment and from this compartment through a second pipepassageway 17, a second casing 12 onto the second impeller thence intothe second cell of the machine.

The pulp is caused to flow thru as many cells in succession in thismanner as practice dictates to be necessary to obtain a proper recoveryof the minerals.

The pulp level, in the individual cells may be regulated by the use ofnarrow cleats 2'7 which are placed on the tops of the weirs 5 and whichmay be used to increase or decrease their height.

The air required for the aeration of the pulp and the formation of thefroth concentrate is automatically drawn into the individual cells ofthe machine from the atmosphere by the rotative action of the impeller20. The air enters the pulp thru the annular space 28 between the solidimpeller shaft 18 and the casing 12 surrounding said solid shaft.

In addition to the flow of the pulp thru the successive cells of themachine, there is provided means to permit of closed circuit agitationof the pulp within each cell. This is accomplished by providing in thestationary horizontal disk 14, a number of holes 29, shown in Figures 2and 4, thru which pulp flows by gravity, falling upon the rotatingimpeller 20.

It is to be understood that various modifications of the foregoing willreadily occur to those skilled in the art, and all such modifications Iclaim as my own if they fall within the scope of the appended claims.

I claim:--

1. In an ore flotation device, a plate to be arranged in a flotationtank and supported in spaced relation to the bottom thereof, a conduitextending vertically from the plate for conducting air to a pointbetween the bottom of the tank and the plate, a driven shaft extendingvertically through the conduit and having its lower end located belowthe plate, an impeller attached to the lower end of the shaft and meansfor discharging ore pulp into the conduit. a plurality of radiallydisposed bafiie plates supported on the plate and cooperating with theimpeller in agitating the pulp.

2. A pulp agitating mechanism comprising: a tank; a shaft verticallysuspended in said tank; an impeller carried on the lower extremity ofsaid shaft; a stationary sleeve spaced from and sur-- rounding saidshaft and terminating above said impeller; and a stationary disk-likeflange surrounding the lower extremity of said sleeve and extendingoutwardly therefrom so as to substantially cover said impeller andprevent pulp from settling thereon.

3. Flotation apparatus comprising in combi-' nation a plurality offlotation cells connected in series, means for continuously supplyingpulp-to the first cell in the series and means for permitting thecontinuous discharge of pulp from the last cell in the series, a rotaryimpeller suspended on a vertical driving shaft in each of said cells, astationary sleeve surrounding and substantially larger in diameter thansaid shaft and extending upwardly from a point adjacent said impeller, acover carried at the lower end of said sleeve and extending over saidimpeller, and a conduit for carrying pulp from one cell and deliveringit to the impeller in the next cell in said series.

4. Flotation apparatus of the character described comprising incombination a plurality of flotation cells connected in series, eachcell having an impeller provided with agitating blades therein suspendedon a vertical driving shaft, a sleeve surrounding said shaft andextending from a point adjacent said impeller to a point above the pulpand froth level in said cell, a cover above said impeller to relieve thelatter of the load of pulp in the upper portion of the cell, and a conduit for carrying the pulp from one cell and delivering it to theimpeller of the next cell.

5. Flotation apparatus of the character described comprising incombination a flotation cell having means for delivering acontinuousstream of pulp to said cell, an impeller provided with agitating bladestherein suspended on a vertical driving shaft, a sleeve surrounding saidshaft and extending from a point adjacent said impeller to a point abovethe pulp and froth level in said cell, a cover for said impeller whichseparates the pulp in the upper portion of the cell from free access tothe impeller blades, and a tube leading from the point of entrance ofpulp to said cell to a point adjacent said. impeller for delivering pulpto said impeller, whereby the pulp entering said tube is obliged to passthrough the impeller before mingling with the pulp in said cell.

6. Flotation apparatus comprising in combination a flotation cell, arotary shaft extending into said cell, an impeller having agitatingblades carried at the lower end of said shaft, a stationary sleevesurrounding said shaft and extending from said impeller to a point abovethe pulp and froth level in said cell, a cover member over said impellerfor carrying the load of pulp in the upper portion of said cell andconduit means for delivering air and pulp to the same side of saidimpeller.

7. Flotation apparatus comprising in combination a flotation cell, arotary shaft extending into said cell, an impeller having agitatingblades carried at the lower end of said shaft, a stationary sleevesurrounding said shaft and extending from said impeller to a point abovethe pulp and froth level in said cell, a cover member over said impellerto carry the load of pulp in the upper portion of the cell so as toprovide air spaces adjacent said impeller and conduit means fordelivering air and pulp together directly to said impeller blades.

8. Flotation apparatus comprising in combination a flotation cell, arotary shaft extending into said cell, an impeller having agitatingblades carried at the lower end of said shaft, a stationary sleevesurrounding said shaft and extending from said impeller to a point abovethe pulp and froth level in said cell, a cover member for separating thepulp in the upper portion of the cell from free access to said impellerblades so as to provide air spaces adjacent said impeller, and air andpulp conduits for delivering air and pulp to said impeller, saidconduits joining each other at a point in advance of the point ofdelivery to said impeller.

9. Flotation apparatus comprising in combination a plurality offlotation cells connected in shaft and extending upwardly from a pointadja-' cent said impeller, said sleeve having an air inlet to allow airto be drawn down the sleeve by the impeller, a cover carried at thelower end of said sleeve and extending over said impeller, and a pulpconduit leading into the cell and connected with said sleeve above saidimpeller to allow the pulp to fall by gravity upon the impeller.

10. Flotation apparatus comprising in combination a plurality offlotation cells connected in series, means for supplying pulp to thefirst cell in the series and means for permitting the discharge of pulpfrom the last cell in the series, a rotary impeller suspended on avertical driving shaft in each of said cells, a stationary sleevesurrounding and substantially larger in diameter than said shaft andextending upwardly from a point adjacent said impeller, said sleevehaving an air inlet to allow air to be drawn down the sleeve by theimpeller, a cover carried at the lower end of said sleeve and extendingover said impeller, said cover being adapted to separate the impellerfrom the full load of pulp in the cell above but having restrictedopenings therethrough to allow a limited access of the pulp in the cellto the impeller to permit recirculation thereof, and a pulp inlet forallowing the entry of pulp from the preceding cell.

11. Flotation apparatus comprising in combination a plurality ofindependent flotation cells connected in series, means for continuouslysupplying pulp to the first cell in the series, means for permitting acontinuous discharge of pulp from the last cell in the series, each cellcomprising abox-like container of substantial depth providing in itsupper part a separating and froth collecting chamber having means forpermitting the discharge of froth therefrom, the lower portion of saidcell below said separating chamber constituting an agitating chamber, arotary agitating impeller in said ,chamber adjacent the bottom of saidcell for producing currents of pulp, means lying above the agitatingimpeller and below the superposed separating chamber for substantiallyconfining violent pulp agitation to said agitating chamber and resistingits transmission to said separating chamber, means for driving saidimpeller to cause the same to agitate the pulp and discharge thesametherefrom into said agitating chamber, an overflow weir formaintaining the pulp level in the cell, and a conduit connecting saidagitating chamber with said weir overflow and opening into the agitatingchamber at a point substantially in the path of a portion of the pulpcurrents created by the impeller and extending in the direction of saidcurrents whereby a portion of said pulp is driven by the impeller intosaid conduit.

l2. Flotation apparatus of the character described comprising aplurality of flotation cells,

each cell comprising a box-like container of substantial depth whichprovides both a pulp agitating zone and a froth-separating'zone, eachcell being provided with a pulp inlet and a tailings outlet, thetailings outlet and the pulp inlet of two adjacent cells being connectedby a passage provided with a weir overflow for controlling the level ofthe pulp in the preceding cell, a rotary agitating impeller in theagitating zone in the lower part of each cell to receive the pulp fromthe pulp inlet and impel currents of pulp outwardly, a bafile above theimpeller for directing the pulp upwardly from the agitating zone and toresist transmission of swirling currents I of pulp to saidfroth-separating zone, said tailings outlet leading from the agitatingzone at a point closely adjacent said impeller and lying in the path ofa portion of said pulp currents whereby pulp may leave said cell withoutcausing disturbance in the froth-separating zone.

13. Flotation apparatus of the character described comprising aplurality of flotation cells, each cell comprising a, box-like containerof substantial depth which provides both a pulp agitating zone and afroth-separating zone, each cell being provided with a pulp inletpassage and a tailings outlet passage, the tailings outlet passage andthe pulp inlet passage of two adjacent cells being connected by apassage provided with a weir overflow for controlling the level of thepulp in the preceding cell, an agitating impeller in theagitating zonein the lower part of each cell to receive the pulp from the pulp inletand impel currents of pulp outwardly, a baille for directing the pulpcurrents upwardly from the agitating zone, the tailings outlet passagehaving an opening in the agitating zone adjacent the impeller andsubstantially in the path of pulp currents expelled by said impeller,said outlet passage leading substantially directly to -21 the overflowweir.

' l4. Flotation apparatus comprising in combination a flotation celladapted to be connected in series with other similar cells, a rotary impeller suspended on a vertical driving shaft near the bottom of saidcell, a stationary sleeve surrounding and substantially larger indiameter than said shaft and extending upwardly from a point adjacentsaid impeller, said sleeve having an air inlet to allow air to be drawndown the sleeve by the impeller, a cover carried at the lower end ofsaid sleeve and extending over said impeller, and a pulp conduit leadinginto the cell and connected with said sleeve above said impeller toallow the pulp to fall by gravity upon the impeller.

ARTHUR WILLIAM FAHRENWALD.

